Massive multiple-input multiple-output antenna techniques provide an effective means for significantly increasing the capacity of cellular communication systems while possibly reducing their energy consumption. Multiple-Input-Multiple-Output (MIMO) antenna techniques are key factors in achieving the high data rates promised by next-generation wireless technologies such as LTE (Long-Term Evolution), LTE-Advanced and 5th generation technologies.
MIMO systems are designed to take advantage of spatial diversity available in the propagation environment. The spatial diversity is quantified by the correlation between antennas, a function of both the propagation environment and the antenna patterns. Under ideal conditions an M×N MIMO system (one using M transmitting antenna elements and N receiving antenna elements) can increase maximum data rates by a factor of min{M,N}times those available from a Single-Input Single-Output (SISO) system operating in the same bandwidth. In other words, a 4×2 MIMO system can (under ideal conditions) double the data rates available in a SISO implementation, while a 4×4 MIMO system can potentially quadruple those rates. However, classical array modeling via MIMO emulation is expensive and prohibitively complex to build, and channel emulators have a limited number of possible inputs.
Development of fifth generation technologies such as 5G wireless telecommunication systems is currently on-going in various organizations. One key differentiator of 5G networks is using massive MIMO to boost capacity by deploying very narrow beams in certain directions. Massive MIMO utilizes many antenna elements, and testing massive MIMO would theoretically require lots of hardware resources. A desire exists to minimize the needed hardware resources, due to both cost and space limitations in testing environments.
Performance testing of a 5G gNodeB (gNB) can be subdivided into over-the-air (OTA) and conductive test methods. These categories can be further subdivided into below 6 GHz and above 6 GHz testing. Many of the 5G frequency allocations are on sub 6 GHz bands.
An opportunity arises to provide systems and methods for conducted, massive MIMO array testing in multiple scenarios. In one case, downlink testing is achieved by emulating broadcast signals from a massive MIMO base station controller to a MIMO mobile unit consistent with a channel model; in another case, uplink testing is carried out by emulating signals from a MIMO mobile unit to a massive MIMO base station antenna array.